This course introduces a number of basic scientific principles underpinning the methodology of cooking, food preparation and the enjoyment of food. All topics covered have a strong basis in biology, chemistry, and physics application. Among others, they include the consumption of cooked food, the physiological and evolutionary implication of the senses, geographic and cultural influences on food, and the rationale behind food preparation. We will also discuss issues such as coupling of senses to improve sense stimulation; altering flavor by chemical means; and modification of the coloration to improve the appearance of dishes. Following the video demonstrations of the scientific principles of cooking, you will learn to recognize the key ingredients and their combinations for preparing good healthy food. At the end of this course, you will be able to: - appreciate the scientific basis of various recipes; - develop your own recipes by integrating some of the scientific principles into new dishes; - recognize the influence of the material world on human perception from the different senses; - appreciate the art of integrating science into cooking and dining. Important Note: This course is not designed for people with special dietary needs such as vegetarian, diabetic, and gluten-free diets. If you feel uncomfortable with any part of the assignments or activities of this course, you can substitute some of the ingredients or ask friends and family members to help with the tasting of your assignments. Alternatively, you may skip that specific assignment provided that you have fulfilled all other qualifying requirement to pass the course.
7.8: What are the prominent tastes in fruits and vegetables?
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来自 The Hong Kong University of Science and Technology 的课程
The Science of Gastronomy
202 个评分
从本节课中
Module 7 and Module 8
This week, we will look at how fruits and vegetables can enhance the quality in cooking and to learn about the properties of meat.
与讲师见面
King L. ChowProfessor
Division of Life Science
Lam Lung YeungAssociate Professor
Department of Chemistry
Talking about fruit and vegetables. We have already covered texture.
We have covered the color. Now, let's look at the taste.
And the three prominent taste that we always want to associate with fruits and
vegetables are the sweetness, the bitterness, and savory.
Now, sometimes we talk about, about the sourness, but then I think that's usually
not our favorite. So let's look at these three tastes and
see what happens. Now, we notice that from most of fruits
when they ripe they would actually reach a level of about ten to 15% of the
weight. actually is made of sugar glucose, so
that's why they are so sweet. And when they're not usually they would
store a lot of their energy in the form of starch.
And the starch usually they are tasteless and actually they give you that plain
texture, very grainy. And, and also at that time usually they
would have a lot of like a sour substance being stored in the fruit.
So, in the way when the fruit is ripening, they're converting of the
starch and the glucose, and the sourness start to go away so therefore, ripe fruit
interface becomes much, much sweeter. Now, on the other hand, when you look at
vegetables. Usually, we seldom talk about vegetables
being sweet but for the vegetable, we are not really probably looking for the, the
taste of sugar. But then usually plant or vegetable gives
you a lot of different kind of texture and the color.
I think that's really most important part of it.
Now, on the other hand, think about the bitterness.
Bitterness usually is associated with some of their, the compound which we call
alkaloid. And what are the alkaloid usually used
for? These are plant metabolize that usually,
they are used for trying to scare the animal away so that they would not eat
them. Now, so therefore you, we, we often see
them in the bark or in the coating of the seeds or so.
And these are used for chemical defense, so that they would be able to survive,
because they're not being eaten up. So, therefore, we play around with this
too. And usually, where do you see that
bitterness? In the seeds.
Now, so it's very easy. You think about yourself.
If your are a plant, and you are in airport, what do you want yourself to be?
You want some animal to come and eat you. But then you want them to sweep the seats
out so that the seats can be like a spread, and you can have a new plan
coming out from somewhere else. Now, so therefore the usually sweet part,
in fact this part is just for attracting animal to eat it, but the seed actually
they don't want you to eat them. Now, there's another taste associated
with plant which will sometimes we didn't realize they exist.
That is the savory part. Remember what savory is about.
Umami, umami is a taste of amino acid. Think about that, a plant in fact using
is just carbohydrates and sugar, no, actually they do have cells.
Cells are made of proteins, too. So therefore if you eat plants, some
plants, they have a lot of cellular content, if they're not just vacuole.
They would have a lot of amino acid component in them.
And when you eat them, in fact, they would give you a sense of umami.
That means they taste good. so with that in fact, we can mix all of
this free and essentially would add into the dish to introduce this free taste.
Of course, there's another one which is about Astringency.
Now, this is a very interesting sense because astringency usually is associated
with a compound which is called tannins. And tannins actually is a, a class of
compounds. And these, again, they are phenolic
compounds with multiple rings. And what they happen is, to do is that
these multiple rings that will be able to associate with some of the salivary
protein to pull them together. To make them form aggregates.
So therefore it generates a feeling of very grainy.
kind of like a feeling. in terms of the texture when this is on
your tongue. So simply, if you don't know what
astringency is about. Think hot, when you're drinking English
tea. And you push your tongue against your
palate. You certainly feel that?
It's a little bit rough, and that's the kind of feeling of astringency.
And most of the time, actually, is also associated with the bitterness, because
tannin in general, they taste bitter. Now, so in order to play around with all
this taste, sometimes we want to have the sweetness.
Because, as I told you earlier, that it reflects that the nutrients that we are
aiming for. we want to have this s-s-s-sweetness as
the primary taste but we don't want to have the bitterness.
We want to have the savory because they taste good.
So, therefore, among the sweet taste, we want to be able to suppress this
bitterness. And this astringency, this roughness,
again by itself, it's not really pleasing.
So, what we want to do is to think of a way to eliminate this astringency.
Remember, these ring associated with protein bring them together to form
aggregate and that give you the astringency property.
In order to eliminate that possibility, the best way to do it is it to prevent
this tannin from associating with all your salivary protein.
So what do you do? What you do is that when we are eating
all of this kind of, of fruits, including for example, these are the fruit that we
obtain from grapefruit or, or from teas or so, they are also astringent.
We would always mix it together with something else.
Now, so remember, we don't want them to cross the salivary protein.
this live reporting so what you do, is try to provide addition of protein to be
associated with this tanning so that they will not be able to pull the salivary
protein together. So combining them together, that's the
strategy that we propose to you. First of all, astringency usually gets
enhanced when it's in a very acidic or in a very salty condition.
So whenever you find something which is astringent, try to stay away from acid
and salt. Okay?
The second thing is that, we see that eat together with sugar.
What happens? Astringen has a component which is about
bitterness. You remember about the taste-taste
interaction. In fact sweetness can suppress
bitterness. So if you eat it together with sugar,
basically it takes care of bitterness already.
And finally, what you do is that a lot of time, mix this astringent food together
with milk. Sometimes meat, sometimes with cheese, so
milk, meat, and cheese these are protein rich food.
And they provide a lot of protein that to compete for this tannin, where your
salivary protein. As a result, if they compete away the
tannin, your salivary protein would not be aggregated and it takes away that
astringency. And of course, sometimes when you have
some food which is rich source of pectin or gum also, they would also carry away
some of this tannin. And of course, the other way that you can
do it, is to try to eat it together with some fats or oil.
That would also smooth it out to prevent the astringency from bothering you.
Now, having all this essentially, we have cover from the very beginning talking
about vegetables. It kind of contribute to the texture.
We talk a lot about the different kind of color, now we talk about taste.
Combine together. Basically, you can think of that, well
maybe your main dish is actually a steak, but then you want to decorate with all
this vegetable. And playing around with the texture,
playing around with the color, and playing around with the taste.
You are basically enriching the exposure. Remember, we want to have the texture
contrast theory at work. In fact, sometimes contrast theory is at
work more than just on the texture. You want to have the contrast of all the
taste, texture, and color, and smell all combined together.
When you can achieve that yes, you can make a good dish.
